Refrigerating mechanism



April 18, 1933. A. J. ASMUSSEN REFIRIGERATING MECHANISM Filed June 6, 1928 gvwento c a QSIZIUkiJQ/Z 61km Mg Patented Apr. 18, 1933 UNITED STATES PATENT, OFFICE AUGUST J. ASIUSSEN', DETROIT, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS, TO I KELVI'NATOR CORPORATION, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN BEFRIGERATING MEUEANISII Application filed June 6, 1928. Serial No. 283,194.

This invention relates to refrigerating apparatus, and particularly to a new and improved type of expansion or freezing chamer or element for the same, the principal 5 object being the provision of a construction that will be eflicient in operation, economical to produce and that will be easier to clean and therefore more sanitary than the conventional t e of expansion chambers now on the mar et.

Another object is to provide an expansion element for refrigerating mechanisms which will remain substantially free of oil during operation of the same.

Another object is to provide an expansion chamber-for refrigerating apparatus comprising a pair of superposed sheet metal plates, the greater portion of the surfaces of which are in substantially contacting relationship with each other.

A further object is to provide an expansion element for refrigerating apparatus com prising a pair of sheet metal plates each cylindrically bent to forma hollow structure 5 of similar section, one of the sheets being inserted into the other thereof with its outer surface in contacting or substantially contacting relationship along the bottom and' sides thereof with the innner surface of the outer sheet, the said sheets'being separated from each other at their upper portions and being sealed along. substantially .parallel lines, to provide what may be termed a crescent-section header and to prevent the escape of refri erantfrom between them.

The a ve being among the objects of the present invention, the same consists in certain features of construction and combinations of parts to be hereinafter described 40 with reference to the accompanying drawing, and then claimed, having the aboveand other objects in view.

In the accom anying drawiiig which illustrates a suita 1e embodiment. of the present invention, and in which like numerals refer to like parts throughout the different views,

- Fig. l'is a vertical sectional view taken as on the line 11 of Fig. 2, longitudinally through an expansion chamber 'or element formed in accordance with the present inventlon. v i

.Fig. 2 is a vertical sectional view taken transversely of the expansion chamber shown in Fig. 1 as on the line 2-2 thereof.

Fig. 3 is a transverse section through a modified form of my expansion element.

Fig. 4 is a side elevation of a modification 'of my invention in which two or moreexpansion element units may be secured together to form a unitary structure of increased refrigerating capacity.

In mechanical refrigerating systems it is necessary, in order to properly lubricate the compressor mechanism, to introduce an amount of lubricating oil into the refrigerant circuit. This lubricant is, of course, circulated through the refrigerant circuit with the refrigerant. In passing through the expansion element where the liquid refrigerant is gasified,-the lubricant is deposited upon the walls of the element and a certain amount thereof is often trapped within such element, the result being that such deposited or trapped lubricant acts as an insulating coating on the inner walls of the expansion element and impedes the transmission of heat between the interior and exterior thereof, which reduces the efliciency of the refrigeratin mechanism a relatively great amount. %)ne of the objects of the present invention is to provide an expansion element which remains free of such coating or trapped lubricating oil at all times.

In the conventional type of expansion elements formed of tubes, not. only is the ori inal cost thereof relatively great due to t e relatively great number of soldered joints necessary and the bulk of metal required, but the soldered joints are liable to rupture during the repeated expansion and contraction of the element due to the variations of temperatures thereof. It is another object of the present invention to provide a construction wherein such tubes and their soldered joints are eliminated and in their place a simple structure formed of sheet metal is provided.

Furthermore, in expansion chambers of the tubular type the construction is such that because of the difiiculties attendant to cleaning the same, impurities are liable to collect on the inaccessible rtions thereof which may have an impairing efifect on the health of the person using the same. The present invention provides a construction in which all surfaces of the expansion element are plain and therefore readily accessible and easily cleaned, having the advantage over conventional constructions in this respect.

The present construction also provides for a minimum volume of refrigerant in the refrigerating system, thereby making it more economical in this respect than the conventional constructions.

Referring to the accompanying drawing I show in Figs. 1 and 2 an expansion element for refri erating apparatus comprised primarily 0% an outer member 10 and an inner member 11. Both members are formed of a single sheet of metal, two opposite edges of the sheet being bent into abutting relationship and there welded or otherwise suitably secured together. The dimensions of the two members 10 and 11 are so related that the inner member 11 is received within the outer member 10 with the outer surface of the member 11 in contacting or substantially contacting relationship with the inner walls of the outer member 10 for substantially the entire area of the sides and bottom thereof, to provide a capillary passage, the members 10 and 11 being slightly separated at or adjacent their top surfaces to provide a relatively small chamber 12 therebetween which serves as a header. The corresponding ends of the portions 10 and 11 are welded together as at 13 so as to seal any space that may be present between the members 10 and 11 against leakage;

Any suitable means may be employed for introducing refrigerant into the device described, that shown being a container 14 suported from the top of the inner member 11 y brackets such as 15. The interior of the container 14 is connected by a tube or passage 16 with the chamber 12 at a point substantially on the level with the bottom of the container 14. A tube 33 is provided between the top of the container 14 and the chamber or header 12 to balance the pressure between the two. provided with a cap or cover 17 which pivotally carries the float member 18 which coacts with the valve member 19 to control the flow of refrigerant into the container 14 from the pipe or tube 20. The container 14 and float mechanism is of that conventional type usually employed in connection with the flooded type of refrigerating systems so that the level of the refrigerant in the expansion element is maintained at the same height as the refrigerant in the container 14. It will be obvious, of course, that any other suitable type of control mechanism may be The container 14 isemployed for feeding refrigerant to the device, whether of the float controlled type, expansion valve, orifice, capillary tube or the like. The gasified refrigerant in the expansion element is removed therefrom through the fitting 21 preferably positioned at the highest point of the chamber 12 and is carried by a tube such as 22 to the compressor in the usual manner.

I prefer to employ methyl chloride in connection with this expansion element although any other suitable type of refrigerant may be employed, and in employing such refrigerant I prefer to maintain it in the expansion chamber above atmospheric pressure. This causes a difference in pressure between the inside and outside of the element which tends to separate the double walls thereof at those points where they lie in contacting relationship so as to permit a small amount of refrigerant to find its way between them. However if it is preferred not to employ methyl chloride or any other refrigerant at pressures greater than atmospheric pressure, such refrigerant or any other refrigerant may be employed at pressures below atmospheric pressure. While pressures greater than atmospheric pressure will expand the metal in the walls of the evaporator and thus increase the space between them, and pressures less than atmospheric pressure will contract the walls of the evaporator thus decreasing the space between them, a space having the proper dimensions to initiate capillary attraction in the refrigerant may be provided in either instance merely by selecting for the construction of evaporators, sheets of metal having the proper type of surface for the service desired. For example, for evaporators operating under pressures greater than atmospheric pressure, relatively smooth sheets of metal may be selected because under pressure the metal will expand slightly to provide spaces of proper dimensions for initiatin capillary action of the refrigerant liquid, w ereas for evaporators operating under less than atmospheric pressure, relatively rough sheets will be selected inasmuch as they will contract rather than expand, but being rough rather than smooth, spaces of dimensions permitting capillary action of the liquid still will be maintained.

In order to prevent too great a separation of the walls, at points intermediate the ends I prefer to secure the walls together in contact with each other at spaced points in any suitable manner, as by rivets such as 23, and sealing the heads of the rivets to their corresponding sheets by brazing or welding rather than soldering.

It will be obvious that with this construction a minimum amount of volume is present between the sheets of the expansion element and that a minimum amount of refrigerant is therefore necessary to maintain a level of refrigerant therein,'and furthermore that in passing from the liquid to a gaseous state the transfer of heat between the refrigerant and the metal ofthe expansion element is extremely rapid because of the close contact of substantially each part of the refrigerant with the metal walls of .the expansion element.

' I have found that with this construction not onlyis it more economical as relates to consumption of refrigerant than the conventional constructions, but that none of the lubricating oil which is carried by the refrigerant is trapped or adheres to the interior walls thereof. I am not satisfied as to the exact reason for this result but it is apparent- 1y a result of the fact that the proximity of the inner and outer sheets to each other form a capillary passage between them which, aided by the boiling refrigerant, carries the oil upwardly to'the discharge opening and thence back to the compressor. Tests have shown that after the present ,expansion element is almost completely filled with lubricating oil and. normal operation is commenced, within a very short period of time all of the oil will be exhausted from the element.

Although this expansion element may be made flat, I prefer to form it into the shape of a hollow structure in order that the interior of the structure may be utilized as a freezin chamber for ice, desserts and the like. l n such a case I prefer to seal one end of the structure with a plate such as 24 and provide two or more shelves 25 therein extending between the opposite side walls, suitable freezing or other trays 26 being slidably received within the element on the shelves 25 for the purpose of carrying the ice or desserts.

In Fig. 3 I show a slightly modified form of the present invention formed of an inner and outer sheet metal cylinder 27 and 28 respectively, the outer walls of the inner cylinder 27 contacting with the inner walls of. the outer cylinder 28 over the lower part of the same and being spaced from each other adjacent the upper part of the same to effect the same result as is effectedin the construction shown in Figs. land 2. q

Where one of the units such as shown in Figs. 1, 2 and 3 is not sufficient to provide the refrigerating capacity required in any particular case, two or more units such as indicated at 29 in Fig. 4 may be provided, each unit 29 beingconnected to the adjacent unit 29 at its upper end by a tube such as 30 and at its lower end by a tube such as 31, as is readily apparent.

While I have shown but two applications of the present invention it will be apparent that it lends itself to variousshapes and forms of expansion elements, and the modification of the construction shown to provide such shapes or forms are within the scope of the ordinary workman.

Formal changes may be made in the specific embodiment ofvthe invention described without departing from the spirit or substance'of the broad invention, the scope of which is commensurate with the appended claims.

sure greater than atmospheric pressure, and

means for introducing refrigerant to and removing it from between said contacting surfaces.

2. A refrigerant evaporator comprising a pair of im erforate members secured together at t eir edges, the greater area of said members normally lying in contacting relationship under the influence of atmospheric pressure between them, and means for introducing and carrying away refrigerant from between said members, at least one of said members being sufliciently resilient to move away from the other of said members under the influence of a pressure slightly greater than atmospheric pressure to permit a film of refrigerant to'flow between said normally contacting areas.

3. A refrigerant evaporator comprising a metallic wall having a capillary passage therein and a vapor collecting chamber connected with said passage, said wall comprising a pair of im erforate'members having a large portion 0 the area thereof normally lying in surface contacting relation, means for supplying refrigerant liquid to said passage and means for exhausting refrigerant vapor from said chamber. 4. A refrigerant evaporator comprising a pair of metallic shells having their adjacent surfaces abutting in one region to provide a capillary passage and separated in another region to provide a vapor collecting member, means for securing said shells together at their edges' for preventing leakage from the aforesaid passage and chamber and means for supplying liquid refrigerant to and for discharging vaporized refrigerant from said evaporator.

5. A refrigerant evaporator comprising a pair of metallic shells having. abutting ad- Jaeent surfaces in one region to provide therebetween a capillary passage and spaced adjacent surfaces in another region to provide a vapor'collecting chamber, means for securing said shells together around their edges, means for securing said shells together intermediate their edges in the region of said abutting adjacent surfaces and means for supplying liquid refrigerant to and for exhausting vaporized refrigerant from said evaporator.

6. A refrigerant evaporator comprising a pair of shells having parallel legs and an intermediate connecting portion, the adjacent surfaces of said shells in the region of said legs being disposed in abutting relation to provide therebetween capillary refrigerant vaporizing passages and said shells being spaced intermediate said legs to pro vide a vapor collecting chamber, means for securing said shells together to prevent leakage of refrigerant therefrom and distortion thereof and means for supplying liquid refrigerant thereto and for discharging vaporized refrigerant therefrom.

7. A refrigerant evaporator comprising a pair of metallic shells having their adjacent surfaces abutting in one region to provide a capillary refrigerant passage and spaced in another region to provide a vaporized refrigerant collecting chamber, said shells being so formed in said capillary passage region as to provide a pair of parallel legs and a connecting bottom portion and in said chamber region being so formed as to provide a top connecting portion, means for securing said shells rigidly together to prevent leakage therefrom and distortion thereof and means for supplying liquid refrigerant to and for discharging vaporized refrigerant from said shells.

8. A refrigerant evaporator comprising a pair of metallic shells having abutting adjacent surfaces in one region to provide a capillary passage and spaced adjacent surfaces in another region to provide a vapor collecting chamber, said shells being also so formed in said capillary passage region and in said chamber region as to provide arcuate and crescent shaped portions respectively, means for securing said shells rigidly together to prevent leakage therefrom and distortion thereof and means for supplying liquid refrigerant to and for discharging vaporized refrigerant from the interior of said shells.

AUGUST J. ASMUSSEN. 

